Gyroscopic compass



Patented Mar. 22, 1932 w I I l UNITED STATES PATENTQFFICTE JAMES .BLACKLOCK HENDERSON, OF LEE, ENGLAND GYROSGOPIG CQMIE ASS Application fil ed June 2, 1921, Serial No. 174,360, and in Great Britain November '13, 19,13. (GRANTED UNDER THE PROVISION-S OF THE HGT 02! MARCH 8, 1921, 41 STAT. I, 1313:)

The object of this invention is to improve rotor axis may bear on a two-par-t-commutagyrostatic compasses more especially with re- .tor carried from the torsion head. 'When gard to the methods of suspension; the methcontact "is made between the brush and tone ods Off damping the precessio-nal movements part the motor nuns one way and when icon- 5 when a displacement'from the meridian octact .is made with the other part it runs in 5 ours; and the prevention of deviation, due the opposite direction, thus eausing :thextorto rolling of the :ship. 1 sion head to tolilow the rotor axis. It now The gyro compass, as invented by Fouthe insulation separating the two commuta- V cault, cons'ists'of a-rotor with horizontal axis tor segments is not ventiea-l but is portion mounted in bearings in acase or ring which of 'a spiral round the vertical central (axis o is pivotally supported on horizontal trun- Off the .rgvroscope, the twist-imparted to-the nions, the trunnion axis beinga little above Wire will be proportional to the angular the centre of gravity of the rotor and easing displacement of the :axis of the rotor trom so that "it has gravitational stability on the the horizontal plane and I arrange the di '16 tIl1l1n l0I1j2LX'lS, th8 position :otstableequilih- .rection of twist so that the .oouple tends to rium being that in which the rotor axis is :bring the :axisback to the horizontal plane. approximately horizontal. The horizontal .Insteadofusinggthesuspension vvireImay trunnion is :earried by -a vertical ring or employ forthi-s purpose a wire attached to frame which is supported on a wire .suspenthe ginibal ring at the lower (end or the version. Such a compass has no damping arrtical diameter.

rangement to bring it to the meridian when Another method of dampingl :may somedisturbed. but otherwise it would keep to times employ is to arrange the trunnion axis the meridian when its axis is properlyaset inclined to the horizontal plane, but still in on the meridian initially, :a small elevation the plane of rotation ofithe rotor. [this has '25 or the rotor axis being necessary. When the :efiect of imparting a twist to the wire '75 used on :a ship vor other moving object the suspension ".When the :axis of the rotor is initorsion head to which the upper end of the ol'i n'ed. wire suspension is attached :must be turned Instead of using :a single filar suspension as the eompass turns .so that there will he li-may employ .a bi-l'larior :trisfilar suspension .no twist in the wire. This may be .done with a distancehetweenthefilars-and I may electrically by means-oi arsuitahle following introduce the electric current required to mechanism. :rlrive the :rotor through the filars.

According to my invention in order .to 1n the Tbi-filar arrangement the gimbal damp (the precession-a1 motion of the rotor ring maybe zdiispensedvviith andt the filarsmay axis and bring it back to the meridian when support the trunnion "axis directly. If the '85 disturbed, I may twist the wire suspension two trunnions are Ifi-xed 5130' the casing on through an angle proportional to the .elevadifierent {levels one above the .eena'tre of the tionof the rotor iaxis above or depression .berotor and the other below, the eitect is the 'low the standard zero position on the merid- :same as "is produced by an inclined trunnion P ian. This zero position can easily lee-brought axis and damping is mai tained. The large 90 into the horizontal plane by su'itablvloading separation vJoetween the filars necessary to the gyro casing so that it will be convenient span the casing :may introduce too vgreat torin what follows to take the horizontal line sional-stability,in whicheventlmay employ in the meridian as the standard position of a yoke "between the ifi'lars above the rotor castheaxis. In order to give the suspension the ingnnd arrange .the'zfilarseloser together be- 95 requiredtwistlmay employ'areversibleelectween the yoke and :the torsion head. The trio motor to twist the torsion head and conadvantage of this sfilar suspension is that the neat the starting s 'tc'h of the electric moiric'tionon the trunnion axis is reducedand is tor with the rotor easing. For example, a amore-oonstant quantitythanin theoase of ibrushicarrliedion'thelcasing in line with \the ball hearings. The @filars may either benee wrapped round the trunnions or clipped to them in any suitable manner.

In another arrangement I may load the rotor casing at the top so that it is in unstable equilibrium on the trunnion axis and support it from the trunnions on a crossed bi-filar suspension, one filar passing through a ring on the other, thereby producing a stable combination when the gyro is running. The damping is arranged as before by having the trunnions on different levels or by turning the torsion head or by other suitable means.

In order to make the period of oscillation of the gyro'compass in the E. W. vertical plane as long as possible, I may employ two small gyroscopes fixed to the torsion head, the two axes of the rotors being in the E. W. direction and opposed and having the rotor casings pivotally mounted on vertical trunnions, the two casings being linked together by toothed wheels or otherwise so that they can only rotate round the trunnion axes in opposite directions and I constrain the motion round the trunnion axes by springs, the standard position of the gyros being that in which their axes of angular momenta are colinear and opposed.

Or, I may employ a single gyro on the torsion head with its axis vertical and mounted on a horizontal trunnion axis in the E. W. direction, the motion round the trunnion axis being constrained bv springs. The pendular motion in the E. W. plane would then produce a pendular motion in the N. S. plane.

I may utilize this last arrangement of an auxiliary gyroscope for diminishing the deviation of the compass due to the ship rolling when 011 a quadrantal course; the rolling mo tion of the ship acting through the gyroscope will cause the compass also to partake of a motion equivalent to the ship pitching with the same period as she rolls. Since the effects of pitching and rolling in producing deviation cancel each other to some extent the deviation will be reduced.

A preferred embodiment of the invention is shown in the accompanying drawings in which Fig. 1 is a vertical sectional View; and Fig. 2 is a detail of the commutator. The gyroscope rotor is mounted to rotate on a horizontal shaft 1 within the casing 2 which is pivoted on a trunnion axis 3 which is inclined to the horizontal. The bearings which support the axis 3 are carried by a ring 4. which is suspended from a torsion head 6 by a crossed bifilar suspension 5a and 5b the filar 5a passing through the ring 50 interposed in the middle of 5?). The torsion head 6 is part of the following element 8 which is pivoted on the compass frame 7 on the vertical tubular axis 8a. The'following element 8 carries the gear ring 9 with which meshes the pinion 10 on the spindle of the small reversible electric motor 11 carried by the frame 7. This motor is controlled by a contact roller 19 pivoted on a fork 18 attached to the gyro case and engaging with a two part commutator 2O fixed to the following element 8. According to whether the roller 19 makes contact with one or other segment of the commutator 20 the motor 11 is actuated in one or other direction so as to make the following element 8 keep in phase with the gyroscope case 2 in a manner well known in the art.

The gyroscope is put in unstable equilibrium about the axis 3 by means of a weight 21.

The gyroscope having been set up arbitrarily with its rotor axis horizontal and the rotor spinning, the rotor axis soon acquires a tilt due to the rotation of the earth and this tilt produces a torque about the horizontal axis perpendicular to-the rotor axis, due to the weight 21 and a torque in the suspension due to the azimuthal displacement imparted to the ring 4 by the tilt of the rotor axis on account of the inclined trunnion axis 3. The torque due to the wei ht 21 produces a horizontal precession of the rotor axis, and the torque due to the suspension, a vertical precession of the rotor axis, and if the direction of rotation of the rotor in this new compass be the reverse of that used in the ordinary Foucault compass the equations of motion are identical with those of the latter and the gyroscope seeks the meridian.

It is essential for a stable combination that the torques due to the suspension shall be in the same direction as the precession due to the gravitational couple. The slope of the trunnion axis 3 and the direction of rotation must be related so that this condition is fulfilled: then the gyroscope, if set up in any azimuth will turn round in azimuth until it finally settles on the meridian with its rotor revolving clockwise as veiwed from the north. that is. with its rotation opposite to that of the earth. This requirement is satisfied by the inclination of axis 3 in Fig. 1 if the rotor is revolving clockwise in that figure, whereas if the rotor were revolving anti-clockwise or if the axis 3 were inclined in the opposite sense the torques in the suspension would tend to oppose the horizontal precession and the gyroscope would try to turn a half somersault on trunnions 3, and if the design of the frame permitted this somersault to take place without fouling, a Foucault compass would result.

It is to be clearly understood that if the direction of rotation of the rotor and the inclination of the trunnion axis 3 are fixed, the stable position of the compass is also fixed, be ing one or the other of two positions in both of which the rotor axis is on the meridian, but in one the gyroscope has turned over until the weight 21 is at the bottom and the gyroscope is rotating in the same sense as the earth whereas in the other the weight 21 is at the top as illustrated and the gyroscope is rotating in the opposite sense to the earth.

1. In a gyro compass, a top heavy gyroscope, means for supporting the gyroscope including a crossed bi-filar suspension and a member within which the gyroscope is mounted upon an inclined axis and to which the suspension is attached.

2. In a gyro-compass, a top heavy gyroscope normally rotated in a counter-c100 wise direction looking north, a member within whichthe gyroscope is mounted for oscillation about a trunnion axis, a supporting element and a connection between the element and the member including a crossed bifilar suspension. 3. In a gyro-compass, a top heavy gyroscope normally rotated in a counter-clock- 2 wise direction looking north, a member within which the gyroscope is mounted for oscillation about an inclined trunnion axis, a supporting'element and a connection between the element and the member including a crossed bi-filar suspension.

4. In a gyro-compass, a gyroscope consisting of a rotor and a case, a member within which the case is supported on an axis inclined at an angle to the horizontal, a member I within which the first member is supported for turning about a vertical axis, and means controlled by the angular position of the case about the inclined axis for applying a torque about the vertical axis.

In testimony whereof I afiix my signature.

JAMES BLACKLOCK HENDERSON. 

